Downhole cables or control lines typically run along the outer wall of an oil or gas well casing. Control lines may be used to provide control information from a surface control unit to downhole devices, and/or provide production information from a downhole device to a surface control unit. It is essential that the downhole cables and control lines are not damaged as a result of well perforation or other ballistics activities.
During well operation, it is common to perforate the well casing in order to create a flow path for the oil and/or gas to flow into the well. This may be done by introducing downhole tools including perforating guns which fire explosive charges through the well casing. As perforations are generally made circumferentially in the well casing, there is a risk that a downhole cable or control line on the outside of the well casing is damaged or broken by an explosive charge. This may render the well inoperable, or at least make operation of the well more difficult.
The present invention seeks to mitigate the above-mentioned problems.